Material reduction mill and classifier



1963 M. E. BOOMER MATERIAL REDUCTION MILL AND CLASSIFIER Sheet 1 3 Sheets- N Filed April 2, 1962 INVE N TOR BOOMER ATTORNEY M ERTON E- Evy Nov. 12, 1963 M. E. BOOMER 3,1 10,447 MATERIAL REDUCTION MILL AND CLASSIFIER Filed April 2, 1962 3 Sheets-Sheet 2 INVENTOR x M RTON E-BOOMER ATTORNEY Nov. 12, 1963 M. E. BOOMER MATERIAL REDUCTION MILL AND CLASSIFIER 3 Shegts-Sheet 3 Filed April 2, 1962 INVENTOR.

M ERTON E- BOOMER United States Patent Ofl ice 3 ,lifiA47 Patented Nov. 12, 1963 3,119,447 RIATERIAL REDU-J'IHQN Mill. AND CLASEEFER The present invention relates to improvements in a ma terial reduction mill and classifier. It consists of the combinations, constructions, and arrangement of parts, as hereinafter described and claimed.

An object of my invention is to provide a mill to reduce or comminute various materials, such as fillers, to a desired degree of fineness.

More particularly, it is proposed to provide a material reduction mill and classifier in which the material is reduced by an impeller that is rotatably mounted in a reduction compartment of a stator housing, the impeller having vanes that are disposed in close relationship with a corrugated inner surface of an attrition ring that surrounds the impeller. The fines are withdrawn by adjustable suction means, while the coarse particles of the material are recycled by improved means for further reduction, the grind being regulated by the magnitude of the suction or negative pressure maintained in the material reduction compartment and the outlet tube leading therefrom, whereby the material is classified by regulating the fineness thereof, and separating the withdrawn fines from the coarse particles.

Another object of my invention is the utilization of the vanes as grinding devices, as well as using them to create a recycling air stream, which will recycle the coarse particles. Also, I propose to utilize the kinetic energy of the recycling air and material to impart motion to the fresh material being fed to the mill. As the speed of the material approaches the speed of the vanes, the abrasive wear is reduced, while the mill efliciency is increased.

Other objects and advantages will appear as the specification proceeds. The novel features of the invention will be particularly set forth in the appended claims.

Drawings For a better understanding of the invention, reference should be had to the accompanying drawings, forming part of this specification, in which:

FIGURE 1 is atop plan view of my material reduction mill and classifier;

FIGURE 2 is a vertical sectional view thereof taken along the plane or line 22 in FIGURE 1;

FIGURE 3 is a horizontal sectional view taken through the material reduction compartment, as indicated by the plane 33 in FIGURE 2; and

FEGURE 4 is a fragmentary vertical sectional view taken along the plane 4-4 of FIGURE 1, illustrating the feed chute for the mill and part of the recycling structure.

While I have shown only the preferred form of my invention, it should be understood that various changes, or modifications, may be made within the scope of the annexed claims without departing from the spirit thereof.

Detailed Description Referring now to the drawings in detail, I have shown a stator housing indicated generally at A, which is mounted on a suitable base B. This stator housing is provided with a material reduction compartment C in an upper part thereof, as clearly disclosed in FIGURES 2 and 3 of the drawings. A substantially vertical shaft D is mounted for rotation in the stator housing A and extends upwardly into the compartment C.

For the purpose of supporting the shaft D, I have provided a bearing housing in which upper and lower bearings 11 and 12, respectively, are mounted. As shown in FIGURE 2, bearing sleeves 13 are provided for these bearings, while upper and lower bearing locknuts 14 and 15', respectively, are secured to the shaft D.

In order to rotate the shaft D, -I have provideda motor E that is carried by the base B. This motor has a grooved sheave 16 on its driven shaft 17, which is connected through belts 18 to a grooved sheave 19' secured to the lower end of the vertical shaft D. A suitable belt tightener 26 has been provided for moving the motor E and its grooved sheave 16 toward and away from the rotor housing A to thus slacken or tighten the belts.

As illustrated in FIGURES 2 and 3, an impeller F is disposed in the compartment C and is secured to the upper end of the shaft D to be turned thereby. This impeller defines a tubular rotor 21 having a plurality of vanes or beater arms 22 swingably secured thereto by vertical pins 23. These vanes project outwardly from the rotor 21 and are movable iuto substantially radial positions when the rotor is turned by the shaft D.

It will be noted that a stationary attrition ring G is arranged in the compartment C to extend circumferentially around the impeller F, and this ring is fashioned with a corrugated inner surface 24 disposed adjacent to the outer ends of the vanes 22, when the latter are swung outwardly during rotation of the impeller (see FIGURE 3).

As shown in FIGURES 1, 2 and 4, a cover H is provided on the top of the stator housing A, and this cover has a passageway 25 extending along the inner circumferential surface 24 of the attrition ring G. A feed chute 26 is connected to the passageway 25 of the cover for delivering incoming material thereto for reduction. This assa ewa communicates with the corn artment C so' P c:

as to drop the incoming material into the compartment between the inner corrugated surface 24 of the attrition ring G and the outer ends of the vanes 22, as will be clear by referring to FIGURE 2 of the drawing.

Referring now to FIGURES 2 and 3, it will be apparent that the tubular rotor 21 is provided with at least one opening 27 in its wall, which places the compartment C in communication with a bore 28 of this tubular rotor. An outlet tube 2? is formed on the top of the cover H and communicates with the bore 28 of the rotor. Suction means designated generally at J is coupled to the outlet tube 29 for drawing fines of the reduced material from the compartment C and through the opening 27 in the tubular rotor 21 for discharge. In operation, a suction blower or fan will provide the suction means.

As an important structural feature, a regulating tube 30 is interposed between the outlet tube 29 and the suction means I, and this regulating tube has at least one opening 31 in its wall extending from its bore to the atmosphere (see FIGURE 2). A rotatable band 33 is mounted on the regulating tube and has one or more openings 34 formed therein. This band may be turned into various positions of closure over the openings in the regulating tube to regulate the amount of air drawn into the bore 32 of the tube 30 and thus control the magnitude of suction established in the tubular rotor 21 during operation of the mill.

It will be noted that the tubular rotor 21 is disposed substantially centrally of the material reduction compartment C so as to withdraw the fines of the reduced material adjacent to the rotor, while the coarse or oversized particles of the material will be thrown outwardly by the vanes 22 to the outer ends of the latter and against the attrition G, thereby providing a centrifugal classifier.

A recycling tube K extends from a lower part of the material reduction compartment C to the feed chute 26 for returning coarse particles of the material back to the compartment for further reduction. The vanes 22 of the impeller F extend into the lower part of the compartment C so as to create a recycling stream of air flowing through the recycling tube K to blow the coarse particles back to the feed chute 26, that is, the coarse particles are entrained by the recycling stream of air. The recycling tube K has a lower branch 35 that communicates with the material reduction compartment C through a spiral passageway 36, the radii of which gradually increases in the direction of rotation of the impeller F (see arrow 37 in FIGURE 3).

Moreover, the recycling tube K has an upper branch 38 that communicates with the feed chute 26 so that the recycling stream of air and the recycled coarse particles of material will intercept fresh incoming'm-aterial being delivered through the feed chute, whereby kinetic energy of the recycling air and coarse particles will impart motion to the fresh material, and thereby reduce abrasive wear in the material reduction compartment C as the speed of all material entering the compartment approaches the speed of the vanes 22.

With particular reference to FEGURE 4, it will be seen that the recycled air and coarse particles enter the cover H through a return port 39, which is inclined downwardly toward the impeller F, the movement of the recycled air and coarse particles being indicated by the arrow 49. The fresh incoming material is delivered through an inlet per 41 in the cover that is inclined downwardly toward the impeller, the'movement of the fresh incoming material being indicated by the arrow 42. Thus the recycled coarse particles are admixed with the fresh incoming material, and there is utilization of the kinetic energy of the recycling air and material to impart motion to the fresh material being fed to the mill.

The amount of material recycled and the resultant fineness of. grind may be easily controlled by adjusting the rotatable band 33 to thereby regulate the magnitude of the negative pressure or suction prevailing in the tubular rotor 21. It will be clear that I utilize the vanes 22 as grinding devices as well as using them for blowing the recycling material. Whenever the material has reached the desired degree of fineness, it will be drawn upwardly by the suction means I to a suitable place of recovery.

I claim:

1. In a material reduction mill and classifier:

(a) a stator housing provided with a material reduction compartment in an upper part thereof;

(b) a substantially vertical shaft mounted for rotation in the stator housing and extending upwardly into the compartment;

(c) means operatively connected to the shaft for rotating the latter;

(d) an impeller disposed in the compartment and being secured to the shaft for turning therewith;

(e) the impeller defining a tubular rotor having a plurality of vanes swingably secured thereto and projecting outwardly from the rotor, the vanes being movable by centrifugal force into substantially radial positions when the rotor is turned;

(f) a stationary attrition ring arranged in the compartment to extend circumferentially around the impeller, and this ring being fashioned with a corrugated inner surface disposed adjacent to outer ends of the vanes, when the latter are swung outwardly during rotation of the impeller;

(g) a cover provided on the top of the stator housing, and having a passageway extending along the inner circumferential surface of the attrition ring;

(h) a feed chute connected to the passageway of the cover for delivering incoming material thereto;

(i) the passageway of the cover communicating with the compartment of the stator housing so as to drop the incoming material into the compartment between the inner corrugated surface of the attrition ring and the outer ends of the vanes for reduction;

(j) the tubular rotor being provided with at least one .4 opening in its wall placing the compartment of the stator housing in communication with a bore of the rotor;

(k) an outlet tube communicating with the bore of the 5 tubular rotor;

(l) and suction means coupled to the outlet tube for drawing fines of the reduced material from the compartment and through the opening in the tubular rotor for discharge.

2. The material reduction mill and classifier, as set forth in claim 1;

(m) and in which adjustable means are provided to regulate the magnitude of the suction established in the tubular rotor and thereby control the grind of the fines withdrawn.

3. The material reduction mill and classifier, as set forth in claim 1;

(m) and in which a regulating tube is interposed between the outlet tube and the suction means;

(it) the regulating tube having at least one opening in its wall extending from its bore to the atmosphere;

(0) and a rotatable band mounted on the regulating tube, and being movable into various positions of closure over the opening in the regulating tube to regulate the amount of air drawn into the bore of this tube and thus control the magnitude of suction established in the tubular rotor.

4. The material reduction mill and classifier, as set forth in claim 1;

(m) and in which the tubular rotor is disposed substantially centrally of the material reduction compartment so as to withdraw the fines adjacent to the rotor, while the coarse particles of the material will be thrown outwardly by the vanes to the outer ends of the latter and against the attrition ring, thereby providing a centrifugal classifier.

5. The material reduction mill and classifier, as set forth in claim 1: V

(m) and in which a recycling tube extends from a lower part of the material reduction compartment to the feed chute for returning coarse particles of the material back to the compartment for further reduction;

(it) the vanes of the impeller extending into the lower part of the compartment so as to create a recycling stream of air flowing through the recycling tube to blow the coarse particles back to the feed chute.

6. The material reduction mill and classifier, as set forth in claim 5;

(0) and in which the recycling tube communicates with the feed chute at a location so that the recycling stream of air and the recycled coarse particles will intercept fresh incoming material being delivered through the feed chute, whereby kinetic energy of the recycling air and coarse particles will impart motion to the fresh material, and thereby reduce abrasive wear in the material reduction compartment as the speed of all material entering the compartment approaches the speed of the vanes.

7. The material reduction mill and classifier, as set forth in claim 6;

(p) and in which the recycled air and coarse particles enter the cover through a return port, which is inclined downwardly toward the impeller, and the fresh incoming material is delivered through an inlet port in the cover that is inclined downwardly toward the impeller.

8. In a material reduction mill and classifier:

(a) a stator housing provided with a material reduction compartment in an upper part thereof;

(b) a substantially vertical shaft mounted for rotation in the stator housing and extending upwardly into the compartment;

(c) means operatively connected to the shaft for rorating the latter;

(d) an impeller disglosed in the compartment and being secured to the shaft for turning therewith;

(e) the impeller defining a tubular rotor having a plurality of vanes swingably secured thereto and projecting outwardly from the rotor, the vanes being movably by centrifugal force into substantially radial positions when the rotor is turned;

(1) a stationary attrition ring arranged in the compartment to extend circumferentially around the impeller;

(g) means for delivering incoming material to the compartment for reduction by the vanes and the attrition Ting;

(h) the tubular rotor being provided with at least one opening in its wall placing the compartment in communication with a bore of the tubular rotor;

(i) an outlet tube communicating with the bore of the tubular rotor;

(j) suction means coupled to the outlet tube for drawing fines of the reduced material from the comyarb ment and through the opening in the tubular rotor for discharge;

(k) and adjustable means to regulate the magnitude of the suction established in the tubular rotor and thereby control the grind of the fines withdrawn.

9. The material reduction mill and classifier, as set forth in claim 8:

(l) and in which the tubular rotor is disposed substantially centrally of the material reduction compartmerit so as to withdraw the fines adjacent to the rotor, while the coarse particles of the material will be thrown outwardly by the vanes against the attrition ring for reduction.

10. The material reduction mill and classifier, as set 5 forth in claim 9:

forth in claim 10;

(0) and in which the recycling tube communicates with the lower part of the material reduction compartment through a spiral passageway, the radii of which gradually increases in the direction of rotation of the impeller.

References Cited in the file of this patent UNITED STATES PATENTS 1,530,654 Daley Mar. 24, 1925 2,355,784 Dondlinger Aug. 15, 1944 FOREIGN PATENTS 562,114 Canada Aug. 19, 1958 

1. IN A MATERIAL REDUCTION MILL AND CLASSIFIER: (A) A STATOR HOUSING PROVIDED WITH A MATERIAL REDUCTION COMPARTMENT IN AN UPPER PART THEREOF; (B) A SUBSTANTIALLY VERTICAL SHAFT MOUNTED FOR ROTATION IN THE STATOR HOUSING AND EXTENDING UPWARDLY INTO THE COMPARTMENT; (C) MEANS OPERATIVELY CONNECTED TO THE SHAFT FOR ROTATING THE LATTER; (D) AN IMPELLER DISPOSED IN THE COMPARTMENT AND BEING SECURED TO THE SHAFT FOR TURNING THEREWITH; (E) THE IMPELLER DEFINING A TUBULAR ROTOR HAVING A PLURALITY OF VANES SWINGABLY SECURED THERETO AND PROJECTING OUTWARDLY FROM THE ROTOR, THE VANES BEING MOVABLE BY CENTRIFUGAL FORCE INTO SUBSTANTIALLY RADIAL POSITIONS WHEN THE ROTOR IS TURNED; (F) A STATIONARY ATTRITION RING ARRANGED IN THE COMPARTMENT TO EXTEND CIRCUMFERENTIALLY AROUND THE IMPELLER, AND THIS RING BEING FASHIONED WITH A CORRUGATED INNER SURFACE DISPOSED ADJACENT TO OUTER ENDS OF THE VANES, WHEN THE LATTER ARE SWUNG OUTWARDLY DURING ROTATION OF THE IMPELLER; (G) A COVER PROVIDED ON THE TOP OF THE STATOR HOUSING, AND HAVING A PASSAGEWAY EXTENDING ALONG THE INNER CIRCUMFERENTIAL SURFACE OF THE ATTRITION RING; (H) A FEED CHUTE CONNECTED TO THE PASSAGEWAY OF THE COVER FOR DELIVERING INCOMING MATERIAL THERETO; (I) THE PASSAGEWAY OF THE COVER COMMUNICATING WITH THE COMPARTMENT OF THE STATOR HOUSING SO AS TO DROP THE INCOMING MATERIAL INTO THE COMPARTMENT BETWEEN THE INNER CORRUGATED SURFACE OF THE ATTRITION RING AND THE OUTER ENDS OF THE VANES FOR REDUCTION; (J) THE TUBULAR ROTOR BEING PROVIDED WITH AT LEAST ONE OPENING IN ITS WALL PLACING THE COMPARTMENT OF THE STATOR HOUSING IN COMMUNICATION WITH A BORE OF THE ROTOR; (K) AN OUTLET TUBE COMMUNICATING WITH THE BORE OF THE TUBULAR ROTOR; (L) AND SUCTION MEANS COUPLED TO THE OUTLET TUBE FOR DRAWING FINES OF THE REDUCED MATERIAL FROM THE COMPARTMENT AND THROUGH THE OPENING IN THE TUBULAR ROTOR FOR DISCHARGE. 